In the first week of January 1856, Mr Henry Lee Norris, an American entrepreneur from New Jersey, and his friend and partner Spencer Thomas Parmelee of Connecticut landed on Scottish soil for the purpose of working a patent of Charles Goodyear for the manufacture of India-rubber overshoes and boots.

The two gentlemen landed in Glasgow and began by searching for a suitable factory, which they eventually found in the form of the Castle Mill in Edinburgh.

Norris brought over the first four employees with him from the USA - Louis Dixon, Sophia Terry, Hannah Dixon and Walter P. Dunn. Early workers from the US had their fares paid both ways and earned the equivalent of around £100 a day, the men receiving 1.5 dollars and the women 1 dollar. The first order was for overshoes from James Dick, who was setting up a gutta-percha shoe-making operation in Glasgow.

From the initial four employees in 1856, NBRC had 600 employees 20 years later. In the early part of the 20th century, the workforce averaged 4000-5000. Peak employment was reached during the Second World War when nearly 10,000 people worked in the Castle Mills. Even in the late 1950s NBRC was employing around 5000 people, largely at the Castle Mills site.

"There were so many people employed there they had to alternate their finishing times through the day so that they would not block the streets from the factory. Most of the workers had faces covered in carbon black because they had been working in the tyre division. It was very difficult to wash off."
— Jim Wilson

Operators learned the tricks of their trade through apprenticeships. Bright apprentices often went on to become Licentiates or Associates of the Indian Rubber Institute by attending ‘rubber schools’. The skills for working many machines, calendars and extruders, in particular, passed from father to son. Training to operate some processes like the spreader for printers’ blanket manufacturer took at least five years.

NBRC liked to claim that their operation was more about people than products or processes, although the company did experience a number of industrial disputes. Generations of the same families worked for the company. It was like a small town with its own culture and social life. Locals claimed that every family in Gorgie and Dalry knew someone who worked in the Rubber.

"When you first started everyone told you that you would get rubber mill fever. The fever only lasted two or three days. It was caused by the smell, the smell from the soapstone. It was white stuff like talcum powder and it got into everything. You always had the smell of rubber in your nostrils, always, it never left you. When my husband came home from the mills, you could smell him coming up the stairs. He couldn’t smell it though."
— Mrs Cairnie